Broadcast channel selecting mechanism having motor operated rotary member

ABSTRACT

A broadcast channel selecting mechanism for all-channel tuning means, arranged so that, in order to make tuning circuits for the respective receivable channels as the circuit of the applied signals to a variable capacity element is switched by a changeover means, the mechanism is provided with a rotary member rotated by a motor and interlocked with the changeover means and having individual different channel positions established thereon for every different rotational angle assumed by the changeover means, and also provided with selected channel position limiting members which are pre-set to those selected ones of the channels in such a way that only in these pre-set positions, the rotation of the rotary member is automatically halted so that any desired channel can be selected.

United States Patent 1 Kimura et al.

[ June 19, 1973 BROADCAST CHANNEL SELECTING MECHANISM HAVING MOTOR OPERATED ROTARY MEMBER Inventors: Sachio Kimura; Yoshiaki Aoki, both of Tokyo-to, Japan Kabushiki Kaisha Kaparu, Tokyo-to, Japan Filed: Nov. 29, 1971 Appl. No.: 202,745

Assignee:

Foreign Application Priority Data Dec.2,l970 Japan ..45/l06549 [52] US. Cl. 334/9, 74/102, 74/104], f 174/ l0.45,-334/l', 334/15, 334/87, 334/88 [511 Int. Cl. H03j 5/18 [58] Field of Search 334/9, l5, 17, 20,

References Cited UNITED STATES PATENTS 7 1972' Midgley etal. 334 15 x Primary ExaminerPaul L. Gensler AttorneyCushman, Darby & Cushman [57] ABSTRACT A broadcast channel selecting mechanism for allchannel tuning means, arranged so that, in order to make tuning circuits for the respective receivable channels as the circuit of the applied signals to a variable capacity element is switched by a changeovermeans, the

mechanism is provided with a rotary member rotated 13 Claims, 11 Drawing Figures LOW TUNER TUNER UHF TUNER PATENIEU 3.740.679

sum 1 I15 5 EH f'Ts o fi l i E i 5 TUNER 1 l on 1:1- F O =55 Q L E a 1 i UHF 1 TUNER iPasi U 3 E I lso; P36 36 TUNING VOLTAGE (v) -Low+ HIGH VHF UHF -l VHF CHANNEHNO.) OR FREQUENCY (MHZ) PAIENIE JUN 1 9 ma satin m 5 BROADCAST CHANNEL SELECTING MECHANISM HAVING MOTOR OPERATED ROTARY MEMBER BACKGROUND OF THE INVENTION 1. Field of the invention The present invention is concerned with a broadcast channel selecting mechanism of tuning means, and more particularly, it relates to a broadcast channel selecting mechanism for tuning means, which can effect the tuning-in to the respective broadcast channels of both the VHF and UHF bands by the use of the same tuning system and which permits the selectable channels to be pre-set in accordance with the location of the receiving site, wherever it may be.

2. Description of the prior art In receiving for example the telecasts of the respective channels in both VHF and UHF bands, there has been used a turret type tuning means for receiving the telecasts in the VHF band, and a sequential tuning type tuning means for receiving the telecasts in the UHF band. However, these tuning means of the sequential tuning type utilizing a variable condenser had the drawback that their tuning operation was considerably complicated and difficult.

Hence, there has been the demand for the development of a tuning means of the switching type for use in receiving telecasts of the UHF band also, in the same way as in the'receiving of telecasts of the VHF band.

As the switching type tuning means for use in receiving telecasts of the UHF band, there are being practiced the following two types, one of which is the mechanical tuning type where the conventional variable condenser is operated by a detent mechanism to function eventially as a sort of switch, and the other is the electronic tuning type where the connection of a variable resistor is changed-over by a switching mechanism so that the applied voltage to a variable capacity diode is regulated.

However, the aforesaid mechanical tuning type tuning means was required to have a high mechanical precision and also it had problems in the aspect of resettability.

On the other hand, in the case of the latter tuning means of the electronic tuning type, there can be obtained one which is markedly superior in such points as the temperature characteristic, the anti-moisture characteristic and the safty. Accordingly, the tuning means of this type is suitable for use as a switching type UHF tuning means.

As the aforesaid electronic tuning type tuning means, there is known one having the arrangement comprising a plural number of changeover switches of dual shaft structure to be operative that the connection of each of these switches can be changed over to any of the LOW VHF band, the HIGH VHF band and the UHF band by the rotation of its outer shaft, and that as its inner shaft is rotated while being depressed, the control voltage is adjusted to have the tuning means pre-set to any selected channel from among the plural number of receivable broadcast channels in the particular band to which the connection of the switch has been changed over, so that at the time of receiving the broadcast, the switch button for the selected pre-set channel is depressed.

A tuning means of the aforesaid type, however, is subjected to a limitation in the number of switches required for the pre-setting of channels. Accordingly, depending on the location of the broadcast receiving site, there may arise the inconvenience that the number of the actual broadcast channels exceeds that of the switches, resulting in the fact that certain broadcast channels cannot be pre-set on, for example, the television receiving set. In order to provide switches in a number covering all of the many broadcast channels, therefore, there is required a space which is large enough to do so. This fact gives rise to an inconvenience in case this tuning means is to be incorporated in a television receiving set. Also, it will be difficult to select a telecast by a remote control device.

SUMMARY OF THE INVENTION It is, therefore, a primary object of the present invention to provide a broadcast channel changeover mechanism of a tuning means for use mostly in all channel television receiving set, which can tune in by the same tuning system to the respective telecast channels of both the VHF and the UHF bands.

Another object of the present invention is to provide a channel changeover mechanism of the type described, which permits the selected channels to be reset as desired so that the receivable channels can be pre-set in accordance with the location of the broadcast receiving site, wherever it may be.

Still another object of the present invention is to provide a tuning means for use in all-channel television receiving set, which has a mechanism arranged so that the respective numbers of the channels are digitally expressed in accordance with the selection of channels.

Other objects and advantages will become apparent from the following description of an illustrative, preferred embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram, showing the electric connections of an example of the tuning means of the present invention;

FIG. 2 is a chart, showing the tuning voltage characteristics of an example of the tuning means of the present invention;

FIG. 3 is a somewhat diagrammatic explanatory illustration, partly broken away and in section and exploded, of an example of the mechanism of the tuning means according to the present invention;

FIG. 4 is a somewhat diagrammatic illustration taken along the line IV-IV in FIG. 3;

FIG. 5 is a somewhat diagrammatic illustration taken along the line V-V in FIG. 3;

FIG. 6a is a somewhat diagrammatic enlarged sectional view taken along the line VIVI in FIG. 3;

FIG. 6b is a somewhat diagrammatic enlarged view taken along the line VIP-VI in FIG. 3;

FIG. 7 is a somewhat diagrammatic explanatory illustration, showing the mechanism for setting and releasing channel pre-setting pins in an example of the tuning means of the present invention;

FIG. 8 is a circuit diagram, showing the electric connections for the channel selecting operations of a tun ing means according to the present invention;

FIG. 9 is a somewhat diagrammatic illustration, showing another example of the mechanism for deriving the output signals of the selected channel in the tuning mechanism of the present invention; and

FIG. 10 is a somewhat diagrammatic illustration, showing another example of the changeover mechanism of the tuning means of the present invention shown in FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, and particularly in FIG. 1, there is shown a block diagram showing the electric connections of the tuning means according to the present invention. The portion enclosed by one-dot-chain line indicated by reference symbol X represents the arrangement of the contacts of switches which are changed. over by the tuning means according to the present invention. In this arrangement of contacts, there are provided a band contact B, for the LOW VHF band, a band contact B for the HIGH VHF band, and channel contacts T T T for the respective channels with respect to the band contact B for the UHF band. A movable contact strip 17 connects between these band contacts and the channel contacts. The respective channel contacts are connected to their corresponding tuning circuits of the LOW VHF, the HIGH VHF and the UHF. More particularly, these channel contacts are connected to voltage-setting variable resistors not shown which are assigned for applying tuning voltages of the respective channels to the tuningvariable capacity diode not shown which are contained in the respective tuners. Holes P P P are formed in a disk 12 which will be described later, to set the positions of connection for the respective channels. Position-limiting pins N N N are disengageably received in the holes P P P respectively, and they are useful in limiting the stopping position of the mov able contact strip 17, and in selecting a channel.

When either a remote control switch SW or an operation switch SW for changing over the channels is depressed, an electromagnet 24 is energized. Whereupon, a switch SW is actuated to close the motor driving circuit containing therein a motor 4, so that this motor 4 is set into motion. In accordance with the rotation of this motor 4, the movable contact strip 17 is shifted in its position.

The curves L L and L shown in FIG. 2 represent the tuning voltage characteristic curves of the variable capacity diodes respesctively contained in the LOW VHF tuner, the HIGH VHF tuner and the UHF tuner which are shown in FIG. 1.

In FIG. 3, the supporting plates 1, 2 and 3 are combined integrally at a portion not shown. A first pulley 5 is mounted on a rotary shaft 4a of the motor 4 rotatably supported by the supporting plates 1 and 2.

A second pulley 7 is rotatably mounted on the shaft 6. The bottom face of this second pulley 7 is provided with a material, such as felt, to provide a frictional face 7a. A belt 8 is applied between the first pulley 5 and the second pulley 7. A third pulley 9 having a gear portion 90 formed integrally around a part of its circumference is fixed on the shaft 6. The upper face of this third pulley 9 is in contact with the frictional face 7a of the second pulley 7. A coil spring 10 urges the second pulley 7 towards the third pulley 9 into contact therewith. A shaft 1 1 is rotatably supported by the supporting plates 2 and 3. A channel selection disk 12 is mounted on this shaft 11. Along the marginal portion of the disk 12 are provided a plurality of holes P,, P P which are formed therethrough in parallel with the length of the shaft 11 (FIG. 3). These holes are provided in a plural number which may be 82 at the most. Also, on the circumferential face of the disk 12, there are provided ratchet teeth R R R equal in number to the holes and in positions corresponding to those positions of the holes. Also, in the middle portion of the circumferential face of the disk 12, there is provided an annular groove 12a which has a depth reaching the holes. The position-limiting pins N N N are received in the holes P,, P P respectively. On the circumference of these respective pins are formed two annular grooves n, and n In FIG. 3, those pins which project downwardly beyond the bottom face of the disk 12 are shown as dual circles in FIGS. 1 and 4 for the sake of convenience. An

elastic belt 13 is applied to the annular groove 12a of the disk 12. This elastic belt 13 is adapted to engage either one of the annular grooves n, and n of each of the pins N N N to semi-fix these pins at their positions in which they protrude beyondeither one of the upper and the bottom faces of the disk 12. A member 15 is fixed to the shaft 11. A gear 14 is secured to the member 15.

The gear 14 meshes with the gear 9a of the third pulley 9. A printed circuit baseplate 16 is provided concentrically with the shaft 1 1, and is fixed to the supporting plate 2.

As will be understood better in FIG. 5, two groups of contacts are provided on a base plate 16 about the shaft 11 concentrically therewith. The inner group of contacts are comprised of three contacts for the changeover of the respective frequency bands, i.e., the band contact B, for the LOW VHF band, the band contact B for the HIGH VHF band, and the band contact 8;, for the UHF band. The outer group of contacts are comprised of channel contacts T T T for applying tuning voltages of the respective channels to the variable capacity diodes. I

These channel contacts areconnected to independent variable resistors, respectively. Alternatively, a coating of resistor is evaporation-deposited directly on the base plate 16. By virtue of the connection established between the band contacts 8,, B and B and the channel contacts T T T there are supplied -to the variable capacity diodes tuning voltages corresponding in magnitude to the connected channels.

The movable contact strip 17 is attached to the disk 12 integrally therewith and forms brushes 17a and 17b which slide between the band contacts 8,, B and B and the channel contacts T T T which are provided on the base plate 16, as the disk 12 is rotated. A shaft 18 is rotatably supported on the supporting plates 1 and 2. A gear 20 is fixed to the shaft 18. The gear 20 meshes with the gear 9a of the third pulley 9. A bobbintype supporting member 19 is fixed to the shaft 18.

As shown in detail in FIGS. 6a and 6b, leaves F F F in a number corresponding to that of the channels are rotatably supported by the supporting member 19. The number of a given channel is indicated jointly by two of these leaves, i.e., by a leaf which is sustained by a holding pawl K and by another leaf which has been turned over downwardly as it was disengaged from the pawl K. For example, in FIGS. 6a and 6b, the number of the selected channel is indicated as being 10 by a leaf F n which is sustained by the pawl K and by another leaf F which has been turned over downwardly.

In FIG. 3, the portion enclosed by one-dot-chain line which is indicated by reference symbol Y is shown in an exploded fashion relative to the other portions.

A rotational angle setting member 21 for use in the pre-setting of selectable channels is rotatably mounted on a shaft 22 which, in turn, is supported by the supporting plate 2. A fourth pulley 21a is provided on the member 21 integrally therewith. A belt 23 is mounted between the third pulley 9 and the fourth pulley 21a.

An electromagnet 24 is provided so as to face the circumference of the disk 12 (FIG. 4). This electromagnet 24 has a pole-contacting member 25 which is urged by a spring 26 in the direction away from the iron core. A pin 27 extends from one end of the pole-contacting member 25. A first arm 28a for operating a self-holding switch SW, of the electromagnet 24 and a second arm 28b for operating a power switch SW,, of the motor circuit are formed at the other end of the pole-contacting member 25. This pin 27 is able to enter into and retreat from the paths of movement of the position-limiting pins N N N of the disk 12. A V-shaped lever 29 has two arms 29a and 29b and is urged to rotate counter-clockwise by a spring 30. The arm 29a of the lever 29 enters into the paths of movement of the positionlimiting pins of the disk 12. The other arm 29b operates a normally closed main switch SW of the energizing circuit of the electromagnet 24. A ratchet pawl 31 is urged by a spring 32 to rotate counter-clockwise and acts upon the ratchet teeth R R R of the disk 12.

In FIG. 7, there is shown a mechanism for operating the position-limiting pins N N N of the disk 12 to deal with the direction of their protrusion. The disk 12 and the position-limiting pins are shown as an integral body at 33 for the sake of convenience. A cover 34 which can be opened and closed about a shaft Q is attached to the manually operable block of the pin operating mechanism. A switch operating member 35 is associated by its arms 35a and 35b with a power switch SW of the electromagnet 24 and also with a first auxiliary switch SW of the motor circuit. When the cover 34 is closed, the switch operating member 35 is pushed by a part of the cover 34 to open the power switch SW by the arm 35a of the member 35 while the auxiliary switch SW is closed by the arm 35b. On the other hand, when the cover 34 is opened, the switch operating member 35 is moved towards the left side in the drawing by virtue of the elasticity of the movable contact strips of the switches SW and SW as the elasticity acts on the arms 35a and 35b of this member 35. In interlocking relation with this movement of the switch operating member 35, the self-holding switch SW which makes the self-holding circuit of the electromagnet 24 moves in the direction of the arrow A shown in FIG. 4 to depart from the sphere of movement of the first arm 28a of the pole-contacting member 25.

A release button 36 for the position-limiting pins is urged towards the left side in the drawing by a spring 37. One end of an intermediate lever 38 engages an end of a rod which extends from the button 36. A pin 38a extends from the other end of the lever 38. A release lever 39 is urged to rotate clockwise by a spring 40. At one end of this lever 39, there are formed a slot 39a for receiving the pin 38a and a projection 39c capable of operating a second auxiliary switch SW of the motor circuit. A pre-setting button 41 for the position-limiting pins is urged by a spring 42 towards the left side in the drawing. A setting lever 43 is urged to rotate counterclockwise by a spring 44. One end of this setting lever 43 engages an end portion of a rod extending from the button 41, and the other end 43a enters into the path of movement of the position-limiting pins.

In FIG. 8, there is shown the circuit for actuating the motor 4 and the electromagnet 24. It should be understood that the switch SW is one for performing remote control operation in switching over the channels. The switch SW is positioned, for example, at the front face of a television receiving set, and it is operated by a channel switching button.

In FIG. 9, there is shown an instance wherein, in

place of the mechanic-to-electric conversion system wherein the connection between contacts is determined by the position assumed by the slidable brushes to make a tuning circuit for a selected channel, there is made a tuning circuit by relying on the magnetic-toelectric conversion system. A shaft 45 is rotatably supported by a supporting plate in an appropriate manner not shown. This shaft 45 is also coupled to a shaft 11 via a gear in a manner not shown so that the shaft 45 is rotated at a speed which, for example, is twice as great as that of the rotation of the shaft 1 1. A magnetizable wheel 46 having projections C C C which are provided at equal intervals on'the periphery thereof is secured to the shaft 45. A permanent magnet 47 is fixed to an attachment member 48 and has an iron core 49 formed on that side facing the magnetizable wheel 46. A coil 50 for detecting a signal is secured to the iron core 49.

I In FIG. 10, there is shown another example with respect to the mechanism associated with the disk 12 and with the electromagnet 24. The members indicated by reference numerals 11, 12 and by reference numerals 24-30 are parts similar to those indicated by like reference numerals in the above-stated example A polecontacting member 25 is provided with a stepped portion 25a. A holding lever 51 having two arms 51a and 51b is urged to rotate counterclockwise by a spring 52 and is rotatably mounted on a shaft 53. In this example, a switch SW is additionally connected between the cir-' cuit of the motor 4 and the circuit of the power source. This switch SW is normally closed and is opened only when its connection is changed over by the arm 29b of the lever 29. The ratchet teeth R R R shown in the preceding example engage, in this example, the pin 27 one at a time to determine the position of the respective channels of the disk 12.

The tuning mechanism having the foregoing arrangements is operated in the manner as described hereunder.

First, in the embodiment shown in FIGS. 3 to 6b, a channel No. 10 is selected. In case it is intended to change this channel over to some other channel, a channel switching button provided on the front side of a television receiving set not shown is operated, so that the switch SW in the circuit shown in FIG. 8 is closed. As a result, the electromagnet 24 is energized, so that its pole-contacting member 25 is attracted thereto against the force of the spring 26 to the position indicated by one-dot-chain line shown in FIG. 4. As a consequence, the pin 27 retreats to the outside of the path of movement of the position-limiting pin N which is received in the hole P of the channel selection disk 12. At the same time therewith, the two arms 28a and 28b of the pole-contacting member 25 cause the selfholding switch SW, and the power switch SW to close,

respectively. Therefore, even when the depression force is removed from the switching button, the electromagnet 24 will henceforth be held continuously in its operative condition, so that the motor circuit is rendered to the closed state. Accordingly, the rotary shaft 4a of the motor 4 is rotated in the direction of the arrow shown in FIG. 3 (this direction will hereinafter be referred to simply as clockwise). This rotation causes the third pulley 9 to rotate clockwise same as the shaft 4a via the first pulley 5, the belt 8, the second pulley 7 and the frictional face 7a. By virtue of this clockwise rotation of the third pulley 9, the channel selection disk 12 is rotated counter-clockwise via the gear 9a, the gear 14, the member 15 and the shaft 11 on the one hand, and the supporting member 19 is rotated counter-clockwise via the gear 9a, the gear 20 and the shaft 18 on the other hand.

In case the disk 12 is rotated counter-clockwise as indicated by the arrow in FIG. 4, it should be understood that the pin N which is received in the hole P of the disk 12 is not protruding therefrom onto the lever 29 side. Accordingly, the arm 29a of the lever 29 will never be brought into contact with the pin N However, the pinN which is received in the hole P is protruding onto the lever 29 side. Therefore, this pin N contacts the arm 29a. As a consequence, this lever 29 is rotated clockwise against the force of the spring 30, so that the switch SW of the electromagnet circuit is opened by the arm 29b of the lever 29. As a result, the electromagnet 24 is de-energi'zed, so that its polecontacting member 25 is returned to the position shown in solid line in FIG. 4. By virtue of this movement of the pole-contacting member 25, the pin 27 enters into the path of movement of the position-limiting pin N Along therewith, the switches SW, and SW5 are both opened. Since the motor 4 will rotate continuously for a short while subsequent to the opening of the switch SW due to inertia, the disk 12 will also rotate accordingly. At a stage of rotation force of the disk 12 at which the disk is almost going to stop, the pin N is brought into contact with the pin 27. Along with this, the disk 12 is halted. In case the motor 4 is still in possesion of some rotation force even after the stoppage of the disk 12, there takes place a slipping between the second pulley 7 and the third pulley 9. Thus, there arises no stress in the whole mechanism. When the disk 12 stops by the engagement of the pin 27 with the pin N the ratchet pawl 31 engages the ratchet tooth R so that any reverse rotation of the disk 12 is arrested.

On the other hand, together with the foregoing movements of the disk 12, the movable contact strip 17 which is fixed to the disk 12 follows the movement of the disk 12. As a consequence, the slidable brushes 17a and 17b are connected to the band contact B of the HIGH VHF band and to the channel contact T respectively. As a consequence, the tuning circuit for the channel No. 12 is completed by the completion of connection, so that the telecast in channel No. l2 may be received. At the same time with the rotation of the disk 12, the supporting member 19 is rotated again. During this part of operation, the leaf F and the leaf F which isomitted are disengaged from the holding pawl K from their state shown in FIGS. 6a and 6b, and they are turned over downwardly. whereupon, the leaves F and F both of which are omitted will then be exposed to indicate the number 12 of the selected channel No. 12. In this way, the telecast channel is switched from the channel 10 over to the state of receiving the broadcast in channel 12.

In case it is intended to effect a further switching of channel, the channel switching member not shown is operated again. Whereupon, the switch SW is closed again. Thereafter, the aforesaid series of operation are repeated. The disk 12 is brought to a halt when the next protruding pin N is positioned in which it contacts the pin 27, and thus the broadcast in channel 13 is selected.

In case a selection of a channel which is the one over the next-positioned channel, i.e., the second channel from the instantly selected one, is desired, the channel switching member is'pushedcontinuously up to the time slightly before the indication of the desired number of channel appears on the channel number indicating section. By doing so, the aforesaid series of operation will be repeated automatically so that the selection of channel is performed quickly.

Also, according to the tuning means of the present invention, it is possible to perform remote control operation with no difficulty. More specifically, by connecting the switch SW shown in FIG. 8 via a cable, this switch SW is operated at a distance from the television receiving set. In this case, a series of operation which are similar to those which would be performed when the switch SW is actuated can be performed. 9

According to the example illustrated, the selectable channels which are pre-set are channel numbers 1, 3, 4, 6, 8, 30, 31 and 34. These pre-set channels will have to be set to comply with the channel arrangement in the individual telecast receiving sites, since the broadcast channel arrangement may differ from each other depending on the countries or districts. In such an event, it is only necessary to operate the manual operating buttons 36 and 41 which are provided in the mechanism for setting and releasing channel presetting pins shown in FIG. 7.

When the cover 34 is opened as a first step, the switch operating member 35 moves the positions of the movable contact strips of the switches SW and SW so that the switch SW is closed while the switch SW is opened. During this part of operation, the self-holding switch SW, of the electromagnet 24 departs away from the scope of action of the first arm 28a of the pole contacting member 25 and it is held in the state of being opened. It is only necessary to depress the release button 36 in order to cause, in the aforesaid state of the switch, the retreat of the position-limiting pins of the channel selection disk 12 which are now protruding onto that side of the disk where the lever 29 is provided. The depression of this release button 36 causes the intermediate lever 38 to be rotated clockwise, so that the release lever 39 is rotated counterclockwise. This counter-clockwise rotation of the release lever 39 causes the second auxiliary switch SW to be closed, so that the motor 4 is rotated accordingly to rotate the disk 12. During this part of operation, the tapered bent portion 39b of this lever 39 is brought into contact with the lower end portions of pins N of the disk 12 which are protruding on that side of the disk where the lever 29 is provided to act to push these pins N toward the other side of the disk 12, so that all of these pins N are caused to protrude onto the other side of the disk 12.

The pins N are held in semi-fixed state by the belt 13 in their respective annular grooves n With the removal of the depression applied to the button 36, the switch SW is opened again, and the motor 4 is brought to a halt and the rotation of the disk 12 ceases accordingly. Subsequently, as the rotation angle setting member 21 assigned for setting channels is manually operated, the disk 12 is caused to rotate together with the supporting member 19. Thereupon, the operation of the member 21 is suspended when this member 21 assumes a position at which the figure indicated by the leaves, as they are turned over in accordance with the aforesaid operation, comes into agreement with the number of channel which is to be pre-set, and the setting button 41 is depressed. Whereupon, the end portion 43a of the setting lever 43 pushes the protruding heads of the pins N so that these pins will be caused to protrude onto the other side of the disk 12 where the lever 29 is provided. By the repetition of these procedures, the pins N are pre-se t in accordance with the channels established at the individual sites of receiving telecasts. Thereafter, by a mere operation of the channel changeover button, the tuning circuit for the desired channel is connected automatically so that the desired telecast can be received.

According to the changeover mechanism assigned for the tuning purpose which relies on the magnetic-toelectric conversion system shown in FIG. 9, one of the projections C of the magnetized wheel 46 passes a point of proximity of the iron core 49 for every partial revolution of the disk 12 corresponding to an individual channel, i.e., l/36th of one whole revolution in case of the example illustrated. At such a moment, there is produced a change in the magnetic energy of the magnetic circuit of the permanent magnet 47 so that pulsating voltages are induced in the coil 50. By counting these pulses as signals, it is possible to effect a shifting the number of channels to such a number as is corresponding to these signals.

To this end, by arranging the electric circuit not shown so that the tuning circuit may be switched over successively by a number corresponding to the number of the pulses produced, with the channel 1 serving as the reference number of channel, it is possible to select the desired channel by means of the aforesaid mechanism. According to such a contact-less arrangement as having been described, there are obtained advantages, with respect to durability and safty, which are geater than those obtained from relying on the system for effecting the changeover operations by the sliding of contact strips on the contacts.

In the aforesaid example, there is selected channel I as the next channel of the channel 36. Therefore, in such a case, the tuning circuit which is adapted to be switched over by the count of the pulses is re-set also,

Let us now assume that the number of the projections of the magnetizable wheel 46 is designated as n, that the rotation speed of the wheel 46 is represented by U, that the number of holes of the channel selection disk 12 is represented by m, and that the rotation speed of the channel'selection disk 12 is represented by V, it is only necessary that the projections be arranged to satisfy the equation: nU mV.

Apart from the aforesaid changeover arrangement designed for the purposeof tuning, there can be utilized also an arrangement relying on optical-to-electric conversion system, though not shown in the aforesaid example.

In the embodiment shown in FIG. 10, the channel is selected as in the preceding example. In case it is intended to change the channel in this state, for example over to channel 12, such a change is accomplished by operating the channel button, in the manner same as that described above in connection with the preceding example. As a result of this operation, the switch SW of the electromagnet circuit is closed, and accordingly its pole-contacting member 25 is attracted thereto (to the position indicated by dotted line). Whereupon, the holding lever 51 which till then has been held at the position indicated by one-dot-chain line by the stepped portion 25a of the pole-contacting member 25 is released therefrom. Accordingly, this freed lever 51 is rotated counterclockwise up to the halt position shown by dotted line. As a result, the pole-contacting member 25 will be held in its attracted position even after the electromagnet 24 is de-energized. The rotation of the motor 4 resulting from the closure of the switch SW is transmitted to the respective coupled members in the same way as that for the preceding example. With the rotation of the disk 12, the arm 29a of the lever 29 is brought into contact with the pin N Whereby, the lever 29 is rotated counter-clockwise against the force of the spring 30, and this rotation of the lever 29, in turn, causes the holding lever 51 to be rotated clockwise against the force of the spring 52. As a result, the pole-contacting member 25 is freed. At the same time therewith, the lever 29 effects the changeover of the switch SW to shut out the supply of power to the motor 4. As a consequence, the rotation speed of the disk 12 decreases, so that the pin 27 of the freed polecontacting member 25 engages the anchoring notch R to hold the disk 12 anchored in this position. In this way, there is obtained a changeover of the channel from 10 to the state of receiving the telecast in channel 12. The remainder of operations and actions is the same as those described in connection with the preceding example.

The indication of channel numbers may be performed by relying on the drum system or the belt system, in addition to the aforesaid leaf system. Also, it is possible to use, as a variable capacity element for the tuning purpose, an element which varies its capacity due to some other factor, in place of using such a variable capacity diode as stated above which varies its capacity by the applied voltage. Also, the number of the channels carried on the disk 12 may be selected as described. Furthermore, the channel selecting mechanism of the aforesaid tuning means may be applied to radio broadcast receiving sets.

We claim:

1. A broadcast channel selecting mechanism of tuning means comprising:

a variable capacity element contained in a resonant circuit and capable of varying its capacity in accordance with an applied signal,

a plurality of signal level setting means connected to said variable capacity element and capable of applying signals of various different levels to said variable capacity element pre-determined in accordance with independently selected channels changeover means associated with said signal level setting means and said variable capacity element and capable of switching the connection between said variable capacity element and the signal level setting means to selectively apply said signals to said variable capacity element,

a rotary means connected to said changeover means for operating said changeover means in accordance with its rotary angle, a motor connected to said rotary means and controlled of its rotation in accordance with the make and break of its switch channel position limiting means on said rotary means at positions corresponding to positions of receivable channels among the positions of all channels provided at spaced intervals for every constant rotational angle of said rotary means,

an electromagnet provided adjacent to said channel position limiting means and having a polecontacting means engageable with said limiting means self-holding means associated with said polecontacting means for holding said pole-contacting means at a position in which said pole-contacting means is attracted to said electromagnet, and a release means provided adjacent to said rotary means and entering into the path of movement of said selected channel position limiting means and being adapted to be shifted in its position immediately before said rotary means is halted by the action of said pole-contacting means applied to the rotating rotary means to thereby set said self-holding means free, said pole-contacting means being adapted to actuate said self-holding means and also to close the motor switch whenever said pole-contacting means is attracted to said electromagnet, and being adapted to depart away from said electromagnet and to halt the rotation of said rotary means upon the, releasing of said self-holding means.

2. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said mechanism further comprises an indicating means interlocked with said motor and driven in synchronismwith said rotary means to digitally indicate the respective receivable channel numbers of all channels.

3. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said variable capacity element is a variable capacity diode capable of varying its capacity by the applied signal voltages.

4. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said changeover means is a mechanism for switching the connection of contacts and comprises slidable brushes and contacts.

5. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said changeover means are electric means adapted to detect the rotational angular position of said rotary means by virtue of a magnetic induction mechanism containing a magnetic head and adapted to changeover the switching circuit connection by virtue of the detected signals.

6. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said selected channel position limiting means are pins protruding onto the face of said rotary means acting upon said release means at the selected position.

7. A broadcast channel selecting mechanism of tuning means according to claim 6, in which said pins are provided so as to be able to protrude and retreat with respect to said face and have notches formed at two positions and are capable of being held semi-fixedly at eical figure to be indicated and being turned over one at a time for said every constant rotational angle assumed by said rotary means.

9. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said selected channel position limiting means comprises pins and notches provided on said rotary means.

10. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said mechanism further comprises a remote control switch connected in parallel with said manually operable switch means.

11. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said selfholding'means is a switch means connected in parallel with the manually operable switch means of said electromagnet circuit.

12. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said selfholding means is a lever adapted to mechanically engage said pole-contacting means of the electromagnet at its attracted position to hold said pole-contacting means at this position.

13. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said rotary means includes a disk and pins having a length greater than the thickness of the disk and they are arranged so that when the pins are in a first position, they protrude onto oneside of said disk to assume the re-setting position and that when the pins are in a second position, they protrude onto the other side of said disk to assume the position of a selected channel; and said mechanism further comprises a normally opened first auxiliary switch of the motor for connecting the motor to a power source; a re-setting lever having a tapered portion operative so that, during a first operation, this tapered portion enters into the path of movement of said pins assuming their first position to cause these pins lying in their first position to move towards their second position one after another, and also having a working portion for closing said auxiliary switch of the motor; a pre-setting lever having a striking portion operative so that, during said second operation, it acts to move the pins assuming their first position towards their second position one after another; a second auxiliary switch of the motor connected in series with said motor switch and arranged so that this serially connected portion is connected in parallel with said first auxiliary switch of the motor; and an electromagnetic switch connected in parallel with said manually operable switch means and operative so that, during each of said first and said second operation, said second auxiliary switch of the motor is opened and said electromagnetic switch itself is closed interlockingly with the opening of said second auxiliary switch.

* l =l #l 

1. A broadcast channel selecting mechanism of tuning means comprising: a variable capacity element contained in a resonant circuit and capable of varying its capacity in accordance with an applied signal, a plurality of signal level setting means connected to said variable capacity element and capable of applying signals of various different levels to said variable capacity element predetermined in accordance with independently selected channels changeover means associated with said signal level setting means and said variable capacity element and capable of switching the connection between said variable capacity element and the signal level setting means to selectively apply said signals to said variable capacity element, a rotary means connected to said changeover means for operating said changeover means in accordance with its rotary angle, a motor connected to said rotary means and controlled of its rotation in accordance with the make and break of its switch channel position limiting means on said rotary means at positions corresponding to positions of receivable channels among the positions of all channels provided at spaced intervals for every constant rotational angle of said rotary means, an electromagnet provided adjacent to said channel position limiting means and having a pole-contacting means engageable with said limiting means self-holding means associated with said pole-contacting means for holding said pole-contacting means at a position in which said pole-contacting means is attracted to said electromagnet, and a release means provided adjacent to said rotary means and entering into the path of movement of said selected channel position limiting means and being adapted to be shifted in its position immediately before said rotary means is halted by the action of said pole-contacting means applied to the rotating rotary means to thereby set said self-holding means free, said pole-contacting means being adapted to actuate said selfholding means and also to close the motor switch whenever said pole-contacting means is attracted to said electromagnet, and being adapted to depart away from said electromagnet and to halt the rotation of said rotary means upon the releasing of said self-holding means.
 2. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said mechanism further comprises an indicating means interlocked with said motor and driven in synchronism with said rotary means to digitally indicate the respective receivable channel numbers of all channels.
 3. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said variable capacity element is a variable capacity diode capable of varying its capacity by the applied signal voltages.
 4. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said changeover means is a mechanism for switching the connection of contacts and comprises slidable brushes and contacts.
 5. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said changeover means are electric means adapted to detect the rotational angular position of said rotary means by virtue of a magnetic induction mechanism containing a magnetic head and adapted to changeover the sWitching circuit connection by virtue of the detected signals.
 6. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said selected channel position limiting means are pins protruding onto the face of said rotary means acting upon said release means at the selected position.
 7. A broadcast channel selecting mechanism of tuning means according to claim 6, in which said pins are provided so as to be able to protrude and retreat with respect to said face and have notches formed at two positions and are capable of being held semi-fixedly at either of their protruding and retreating positions by the engagement of an elastic member located in the rotary means with either of the notches.
 8. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said indicating means is a group of leaves each carrying a numerical figure to be indicated and being turned over one at a time for said every constant rotational angle assumed by said rotary means.
 9. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said selected channel position limiting means comprises pins and notches provided on said rotary means.
 10. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said mechanism further comprises a remote control switch connected in parallel with said manually operable switch means.
 11. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said self-holding means is a switch means connected in parallel with the manually operable switch means of said electromagnet circuit.
 12. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said self-holding means is a lever adapted to mechanically engage said pole-contacting means of the electromagnet at its attracted position to hold said pole-contacting means at this position.
 13. A broadcast channel selecting mechanism of tuning means according to claim 1, in which said rotary means includes a disk and pins having a length greater than the thickness of the disk and they are arranged so that when the pins are in a first position, they protrude onto one side of said disk to assume the re-setting position and that when the pins are in a second position, they protrude onto the other side of said disk to assume the position of a selected channel; and said mechanism further comprises a normally opened first auxiliary switch of the motor for connecting the motor to a power source; a re-setting lever having a tapered portion operative so that, during a first operation, this tapered portion enters into the path of movement of said pins assuming their first position to cause these pins lying in their first position to move towards their second position one after another, and also having a working portion for closing said auxiliary switch of the motor; a pre-setting lever having a striking portion operative so that, during said second operation, it acts to move the pins assuming their first position towards their second position one after another; a second auxiliary switch of the motor connected in series with said motor switch and arranged so that this serially connected portion is connected in parallel with said first auxiliary switch of the motor; and an electromagnetic switch connected in parallel with said manually operable switch means and operative so that, during each of said first and said second operation, said second auxiliary switch of the motor is opened and said electromagnetic switch itself is closed interlockingly with the opening of said second auxiliary switch. 